Jet-propelled aircraft with means for thrust deflection

ABSTRACT

Jet aircraft having means for deflecting the thrust thereof for control purposes. Deflecting means are normally received into a suitable recess in structure adjacent the jet stream such as the horizontal stabilizer, the vertical stabilizer or the fuselage rearward of the jet output. Same are then actuated by any conventional means to extend the deflectors into the jet stream during slow speed operation of the aircraft and retracting same to permit during high speed operation of the aircraft all control functions to originate with the stabilizers, elevators and rudder. A further feature of the invention contemplates mounting the deflectors in a component movable with respect to the jet output, such as the elevators, with the elevators normally located below the jet output whereby the deflectors can be extended without entry into the jet stream at substantially level flight but will move gradually into the jet stream as said elevators are lifted during a landing operation.

ll'nited States Patent '[191 Mederer 1 JET-PROPELLED AIRCRAFT WITH MEANSFOR THRUST DEFLECTION [75] Inventor: Andreas Mederer, Marktschwaben,

Primary Exbminer-TrygveM. Blix Attorneywoodhams, Blanchard & Flynn [451Ma 1 R973 57 Answer" Jet aircraft having means for deflecting the thrustthereof for control purposes. Deflecting means are normally receivedinto a suitable recess in structure adjacent the jet stream such as thehorizontal stabilizer, the vertical stabilizer or the fuselage rearwardof the jet output. Same are then actuated by any conventional means toextend the deflectors into the jet stream during slow speed operation ofthe aircraft and retracting same to permit during high speed operationof the aircraft all control functions to originate with the stabilizers,elevators and rudder. A further feature of the invention contemplatesmounting the deflectors in a component movable with respect to the jetoutput, such as the elevators, with the elevators normally located belowthe jet output whereby the deflectors can be extended without entry intothe jet stream at substantially level flight but will move graduallyinto gthe jet stream as said elevators are lifted during a landingoperation.

7 Claims, 4 Drawing Figures JET-PROPELLEI) AIRCRAFT WITH MEANS FORTI-IRUST DEFLECTION The invention relates to a jet-propelled aircraftprovided with means for effecting thrust deflection for controlpurposes.

This type of control assures an effectiveness independent of flyingspeed. It is of particular importance for V/STOL aircraft that they becompletely under control during the critical takeoff or landing phaseduring which inflow velocities are either very low or completely absent.

It is already known to the prior art to deflect the jet efflux flowingfrom the tail of an aircraft by having the entire nozzle rotate eitherin any direction or in at least two planes. However, this designinvolves weight and cost penalties that are not in every case justifiedfor all applications of this kind. For example, in most cases, it issufficient if the means for thrust deflection is availa ble for only thecritical takeoff and landing phases, while at mission speeds theaerodynamically functioning control surface is preferred, especially dueto its natural" stabilization and damping-properties. In addition, thereis a desire to make the thrust deflection unit as simple and light aspossible. It is therefore also known to the prior art, especially in thecase of missiles, to effect deflection of the gas efflux by means ofdeflectors that project into the jet stream (Koelle, Theorie und Technikder Raumfahrzeuge, Stuttgart 1964, pages 387388). However, this knowndevice has the drawback that the deflection surfaces remain in the jetstream during the missiles entire propulsion phase and cause detrimentaldrag. In contrast to a missile, whose flight consists of a relativelybrief power-on phase and a long free flight, the engines of an airplaneoperate as a rule during the entire flight, so that the proposaldescribed above would not be without objectionable features when appliedto aircraft.

It is the object of the present invention to provide a thrust deflectiondevice for aircraft of the type mentioned above, which is light anduncomplicated and which can be operated by the pilot selectively duringtakeoff or landing, at high altitudes and low atmospheric pressures orin combat.

The invention solves this problem by having the deflection means consistof deflection surfaces that swing into the jet stream. These deflectionsurfaces can be actuated in a known manner with respect to the directionofjet flow so that this flow is deflected.

In one illustrative embodiment, especially in an aircraft with jetnozzles at the tail and an auxiliary control surface locatedapproximately at the same station as the nozzle, it is provided that thedeflection surfaces rotate about an axis which is approximatelyperpendicular to the horizontal tail and that they swing from aretracted, inoperative position located within the contour of thestabilizer into an operating position projecting into the gas stream. Inthis way the stowage problem for these deflection surfaces is solvedadvantageously as they add to the overall area of the stabilizer when intheir inoperative position. A further advantage is that actuation of thedeflection surfaces in a known way izer and be accommodated in anappropriately sized recess therein so that they are flush with thestabilizer trailing edge when in the closed position. Thus, anespecially effective and technically advantageous solution has beenfound which has no detrimental projections or vortex-producing cornerson the stabilizer surface, which latter is itself designed in accordancewith pure aerodynamic rules.

In another illustrative embodiment the stabilizer is located a certaindistance below the jet nozzle axis so that when the stabilizer is in theneutral position, the deflection surfaces are, in their operativeposition, not in contact with the jet and when the stabilizer is fullydeflected, they assume their position of maximum effectiveness in thegas stream. This solution allows the pilot to swing the deflectionsurfaces into their operative position at a time when they are not yetneeded, so that he is relieved of this task during the ensuing criticalflight phase. Also, sudden changes in control moments are prevented, asthe deflection surfaces, upon operation of the stabilizer, move from arange outside the jet stream, penetrating continuously farther into thejet stream, until they reach their position of maximum effectiveness.

For an aircraft with two side-by-side nozzles in the tail and a tailcone which extends over the nozzles toward the rear, anotherillustrative embodiment provides that the control surfaces swinglaterally into the gas stream and are controlled by control devicesaccommodated in the tail cone. These control devices can workindependently of, or in conjunction with, the control devices for theaerodynamic control surfaces, if any.

The invention is employed essentially for pitch control in the foregoingdescription. Naturally, it can also be used for yaw control, in whichcase the deflection devices can be accommodated in the rudder.

Several illustrative embodiments are depicted in the drawings and aredescribed in more detail hereinafter.

Shown are:

FIG. 1 is a plan view of the tail of a twin jet aircraft with ahorizontal tail at approximately the same station as the nozzles;

FIG. 2 is an aircraft tail according to FIG. 1, but seen from the side;

FIG. 3 is an aircraft tail with a tail cone extending toward the rearover the nozzles, shown in plan view; and

FIG. 4 is an aircraft tail according to FIG. 3, but seen from the side.

FIGS. 1 and 2show a fuselage tail section 1 in which two engines 2, 3are located side-by-side. At the sides of the fuselage are the twostabilizers of the horizontal tail 6. At the trailing edge of eachstabilizer are the deflection surfaces 7, 8 which rotate about axesapproximately perpendicular to the stabilizer surfaces. In theirinoperative condition they are completely retracted into the contour ofthe stabilizers 4, 5, while in the operation position, they penetratecompletely into the adjacent jet stream 9 or 10.

FIG. 2 shows that when the stabilizer 5 is at a certain angle above theneutral position, the deflection surface moves into the area of theexhaust gas 10. This feature permits the pilot to actuate the extensionmechanism for the deflection surfaces prior to the anticipated criticallanding phase, for example, as early as the landing approach, before theend phase. In addition, the action of the deflection surfaces does notcommence suddenly, but increases continuously as the surfaces penetrateinto the exhaust stream from below.

The dot and dash line in FIG. 1 denotes a reduced area with respect tothat of horizontal tail 6 which is brought about by the fact that theaction of the aerodynamic stabilizer is assisted by the effect of thethrust deflection. For this reason, it is no longer necessary to designthe stabilizer surface for the rotation," the sudden increase in angleof attack upon liftoff, but it is sufficient to have the smaller tailsurface which suffices for highspeed flight. As is shown in FIG. 2, thedeflection surface works in the same sense as the stabilizer, i.e., inthe example shown, the aircraft tail is moved downwards so that a noseup moment is produced for the entire airplane.

FIGS. 3 and 4 show a solution for the case in which the stabilizer isabsent or in which it is in the form of a canard or stabilator. In thiscase, the deflection surfaces 20, 21 are accommodated in the tail cone25 which extends rearward over the nozzles 22, 23 and are swung outwardsfrom the sides into the adjacent jet stream.

The profile of the deflection surfaces is preferably a supersonicprofile of the known type, for example, a wedge profile 24 or a doublewedge profile, not shown.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:

1. In an airplane having a vertical tail surface and a horizontal tailsurface and means for supporting a jet engine adjacent said horizontaltail surface, said jet engine producing a gaseous stream for propellingsaid airplane, the combination comprising:

deflection means for deflecting said gaseous stream,

said deflection means including surface means and support means forsupporting said surface means for pivotal movement between first andsecond positions about an axis which is substantially perpendicular tosaid horizontal tail surface; and storage means on said horizontal tailsurface for storing said surface means in said first position, saidsurface means being pivotable about said support means to said secondposition wherein said surface means is adapted to contact and deflectsaid gaseous stream.

2. The combination according to claim 1, wherein said surface means hasan outer contour conforming to the outer contour of said horizontal tailsurface when in said first position.

3. The combination according to claim 2, wherein said surface means islocated on the trailing edge of said horizontal tail surface and whereinsaid storage means comprises a recess of appropriate size in saidhorizontal tail so that said surface means is flush with said trailingedge.

4. The combination according to claim 3, wherein said horizontal tailsurface is located below the axis of said gaseous stream so that whensaid horizontal tail surface is in a neutral position and said surfacemeans is swung into said first position, said surface means is free ofcontact with said gaseous stream and when said horizontal tail surfaceis at said second position, said surface means is in the position ofgreatest deflection effectiveness or said gaseous stream.

5. The combination according to claim 4, wherein said airplane has apair of thrust nozzles side-by-side and wherein said horizontal tailsurface has a pair of surface components, said storage means storing oneof said surface means on each of said surface components of saidhorizontal tail surface, each of said surface means being pivotal aboutan axis substantially perpendicular to said horizontal tail surface.

6. In an airplane having at least a vertical tail and means forsupporting a jet engine, said jet engine producing a gaseous stream atan outlet nozzle for propelling said airplane, the combinationcomprising:

surface means positioned adjacent said outlet nozzle;

support means for supporting said surface means for pivotal movementbetween a first position of use and a second stored position about asubstantially vertical axis parallel to said vertical tail and which issubstantially perpendicular to said surface means, said surface meansbeing adapted to contact said gaseous stream to deflect same when insaid first position of use and stored in a position of nonuse when insaid second position.

7. Aircraft according to claim 6, wherein said airplane has a pair ofjet nozzles side-by-side on opposite sides of a tail cone that extendsrearwardly of said nozzles and wherein said surface means each isswingable out of the tail cone sideways into said gaseous stream. 7

1. In an airplane having a vertical tail surface and a horizontal tailsurface and means for supporting a jet engine adjacent said horizontaltail surface, said jet engine producing a gaseous stream for propellingsaid airplane, the combination comprising: deflection means fordeflecting said gaseous stream, said deflection means including surfacemeans and support means for supporting said surface means for pivotalmovement between first and second positions about an axis which issubstantially perpendicular to said horizontal tail surface; and storagemeans on said horizontal tail surface for storing said surface means insaid first position, said surface means being pivotable about saidsupport means to said second position wherein said surface means isadapted to contact and deflect said gaseous stream.
 2. The combinationaccording to claim 1, wherein said surface means has an outer contourconforming to the outer contour of said horizontal tail surface when insaid first position.
 3. The combination according to claim 2, whereinsaid surface means is located on the trailing edge of said horizontaltail surface and wherein said storage means comprises a recess ofappropriate size in said horizontal tail so that said surface means isflush with said trailing edge.
 4. The combination according to claim 3,wherein said horizontal tail surface is located below the axis of saidgaseous stream so that when said horizontal tail surface is in a neutralposition and said surface means is swung into said first position, saidsurface means is free of contact with said gaseous stream and when saidhorizontal tail surface is at said second position, said surface meansis in the position of greatest deflection effectiveness or said gaseousstream.
 5. The combination according to claim 4, wherein said airplanehas a pair of thrust nozzles side-by-side and wherein said horizontaltail surface has a pair of surface components, said storage meansstoring one of said surface means on each of said surface components ofsaid horizontal tail surface, each of said surface means being pivotalabout an axis substantially perpendicular to said horizontal tailsurface.
 6. In an airplane having at least a vertical tail and means forsupporting a jet engine, said jet engine producing a gaseous stream atan outlet nozzle for propelling said airplAne, the combinationcomprising: surface means positioned adjacent said outlet nozzle;support means for supporting said surface means for pivotal movementbetween a first position of use and a second stored position about asubstantially vertical axis parallel to said vertical tail and which issubstantially perpendicular to said surface means, said surface meansbeing adapted to contact said gaseous stream to deflect same when insaid first position of use and stored in a position of nonuse when insaid second position.
 7. Aircraft according to claim 6, wherein saidairplane has a pair of jet nozzles side-by-side on opposite sides of atail cone that extends rearwardly of said nozzles and wherein saidsurface means each is swingable out of the tail cone sideways into saidgaseous stream.